Vol 7, No 4 (2016)

In the first decade of the 21th century, the findings of a new invader, the American rotifer, Kellicottia bostoniensis (Rousselet, 1908), has become more frequent in Russia. By 2015 K. bostoniensis had been detected in more than 40 different waterbodies and watercourses of European part of Russia. American rotifer is a widely spread and common species in forest lakes and rivers of the Baltic Sea basin, Volga-Baltic watershed; in the Volga River basin it has spread southward to 55° N (lakes of the Oka and Pra rivers) and eastward to 45° E (the Kerzhenets River, Cheboksary Reservoir basin). The rotifers inhabit small (<3 km²) and large (>200 km2), shallow (<1 m) and deep (>20 m) waterbodies with a trophy range from oligo- to eutrophy. In Russia K. bostoniensis occurs in a wide range of color of water (30–680 degrees Pt–Co-scale) compared to waterbodies of Western Europe. The rotifer is tolerant to temperature regime and oxygen concentrations in water. In the hypolimnion of stratified lakes, K. bostoniensis reaches high abundance (>100000 ind./m3) at a very low concentration of dissolved oxygen (2.5 mg/L or about 20% of saturation) and water temperature of 5–12°С. The invader and aboriginal species K. longispina coexisted in deep lakes and deep parts of reservoirs (the depth more than 5 m); in shallow lakes only K. bostoniensis was found. On the contrary, in most parts of large reservoirs of the Upper Volga only K. longispina was recorded. The possibility and the direction of transfer of the rotifer by swimming birds are discussed.

This paper presents the information on the history of appearance, modern composition, and distribution of fish species that have been introduced by man or have settled independently in the water bodies of the Krasnoyarsk Territory since the early 20th century. It is shown that the fish fauna composition has expanded mainly in the basin of the upper and middle Yenisei as well as in the basin of the Chulym that is a right tributary of the Ob; the fish fauna of the Pyasina and Khatanga rivers that are beyond the Arctic Circle has remained unchanged. Eleven fish species and two subspecies are new for the region; among them, common bream and sunbleak have largely expanded their range in the Yenisei and Chulym basins; pike perch, Amur sleeper, and bleak have enlarged their range only in the Chulym basin. The spread of other species is limited by the regions of their artificial stocking. Peled that is common for the northern regions of the territory was resettled in the Krasnoyarsk Reservoir; the status of Prussian carp that was introduced from the Amur River and degree of its assimilation with the local populations of this species are not clear.

Overview of changes that occurred in the inland waters of the Crimea is presented, and the introduction and naturalization of alien fish species, associated with this process, is studied. Approximately 55 new fish species were registered in the last 70 years in rivers, reservoirs, canals, and ponds of the peninsula. They can be attributed to four groups according to their abundance: (1) their findings are single, (2) they lived in the waters during several decades and disappeared over a given period, (3) their presence and number depends on aquaculture activities, and (4) they created sustainable self-reproducing populations. Currently, at least 27 species of fish can be considered as naturalized. The distribution and quantitative characteristics of alien species in the rivers and reservoirs of the North Crimean channel and their relationship with biotopical and hydrological characteristics of the habitats are analyzed.

This paper presents the results of analysis of the population dynamics of Eurasian beaver after its reintroduction into the Lapland, Darvinsky, Central-Forest, Prioksko-Terrasnyi, Oksky, and Khopersky natural reserves that are located in European Russia in the northern, southern and central parts of the beaver range. The paper analyzes the effectiveness of a discrete time model that includes a feedback between animals and their food resources for the quantitative description of the population dynamics in the optimal, suboptimal, and pessimal habitats. It is shown that the beaver population dynamics demonstrates four grows types (patterns): the eruptive type (Lapland Reserve); single-stage type with a quasi-periodic oscillation (Prioksko-Terrasnyi Reserve), multi-stage type with quasi-periodic oscillations (Darvinsky, Central-Forest, and Khopersky reserves) and the logistic curve of population growth with periodic oscillations around it (Oksky Reserve). The biotic and abiotic factors that determine these types of animal population dynamics are discussed.

In June–August of 2012–2013, changes in the structure of multispecies ant assemblages caused by invasive plant species Impatiens parviflora in deciduous forests of the green zone of Kiev, Ukraine, were studied. This species–transformer is able to penetrate into ecosystems and change their shape by forming single–species thickets. Data on ant’s attendance of each of the 7 species of herbaceous forest plants were compared. The comparison showed that I. parviflora is the most attended herbaceous forest plant by ants. Fourteen ant species were found in the areas where I. parviflora dominated in the grass layer. Three species of ants, Formica rufa, Lasius fuliginosus, and L. emarginatus, are dominants. When becoming a dominant species in the grass layer of forests, I. parviflora is attended mainly by influent ant species. The main resource provided by I. parviflora to ants is the sugary excretions of aphids Impatientinum asiaticum colonies. Dominant ant species, except for L. emarginatus, do not attend I. parviflora plants, which gives the ability of creating high dynamic density in the grass layer to influent species without the influence of dominants. Influents prefer to attend the herbaceous layer, whereas dominants prefer the ground layer. Influence of I. parviflora on quantitative parameters in multispecies ant assemblages is generally estimated positively. In plant communities, where I. parviflora dominates in the grass layer, the assemblages of ants are characterized by maximum values (ant species number and medium number of ants per sample) compared with other communities formed by native herbaceous plants.